The present invention relates to a process and apparatus for purifying waste gases by scrubbing with an adsorbent suspension which contains at least one finely dispersed adsorbent which is fed continuously to at least one gas-scrubbing device, distributed therein and contacted with the waste gas. In such a process, the pollutants, impurities or the substances which are to be separated off, or parts thereof, are converted, degraded and/or chemically or physically modified by biological means and subsequently wholly or partially separated off.
The adsorbent suspension in a relatively high average use concentration is distributed uniformly or almost uniformly in the gas-scrubbing device and has a very short residence time or a relatively high passage velocity therein, while it is passed subsequently into at least one reactor, arranged separately from the gas-scrubbing device and containing aerobic bacteria, and is treated therein at a very much longer residence time with forced motion, the biological conversion of impurities taking place.
Similar processes, are disclosed, for example, in German Offenlegungsschriften 3,227,375 and 3,345,944. However, in the known processes activated sludges and/or other biological solids are deposited in considerable thicknesses on the adsorbent material, active beds are blocked by growth, or the activity of the adsorbents is blocked to a considerable extent, so that the effect of the adsorbents is very considerably weakened and, after a certain time, the adsorbent then serves more or less only as a carrier material.